This disclosure relates to a processing that includes a first shell and a second shell disposed within the first shell. The second shell includes a first end, a second end, and a wall extending between the first end and the second end. The second shell also defines a cavity and a longitudinal axis extending between the first end and the second end. A cross section of the second shell transverse to the longitudinal axis includes a first arcuate inner wall portion having a first radius of curvature and a second arcuate inner wall portion having a second radius of curvature. The first radius of curvature is larger than the second radius of curvature.

The invention discloses a stirring rib (100), a stirring mechanism and a cooking robot. The stirring rib includes a first rotating shaft (110), a second rotating shaft (120), a first connecting rod (130), a second connecting rod (140), a first extending rod (150), a second extending rod (160), and a stirring blade (170). The first connecting rod is connected to one shaft end of the first rotating shaft and is arranged in a downward extending manner. The second connecting rod is connected to one shaft end of the second rotating shaft and is arranged in a downward extending manner. The first extending rod is connected to a bottom of the first connecting rod. The second extending rod is connected to a bottom of the second connecting rod.